Patterning mechanisms for knitting machines

ABSTRACT

A patterning mechanism for a knitting machine comprising a bank of selector elements each associated with individual electromagnetic means for movement between selection and non-selection positions, in which means is provided to constrain the magnetic flux produced by the electro-magnetic means to follow a predetermined magnetic path whereby the influence of any electromagnetic means upon any selector other than the associated selector is reduced to negligible proportions.

United States Patent [191 Wade et a1.

[ PATTERNING MECHANISMS FOR KNITTING MACHINES Inventors: Thomas CyrilJames Wade, Harcourt; 1an Matthewson, Fleckney; Sidney Clifford Savage,Wigston Magna, all of England Wildt Mellor Broimley Limited, Leicester,England Filed: May 21, 1971 Appl. No.: 145,824

Assignee:

Foreign Application Priority Data May 22-, 1970 Great Britain 25043/70us. Cl ..-....'66/5 0 R rm. Cl D04b 15/78 Field of Search. 66/50 R, 50B, 25, 75,

References Cited UNITED STATES PATENTS 3,492,836 2/1970 Blood et a1.66/155 X [ll] 3,810,368 [451 May 14, 1974 1,560,778 11/1925 Goddard200/166 L 3,550,398 12/1970 Widdowson 66/50 R 2,439,126 4/1948 Buttrey200/166 L Primary Examiner-Wm. Carter Reynolds fl .9f izu aq ameifymiwsiqm tlias le were Weintraub 7 A patterning mechanism for aknitting machine comprising a bank of selector elements each associatedwith individual electro-magnetic means for movement between selectionand non-selection positions, in which means is provided to constrain themagnetic flux produced by the electro-magnetic means to follow apredetermined magnetic path whereby the influence of anyelectro-magnetic means upon any selector other than the associatedselector is reduced to negligible proportions.

- ABSTRACT 4 Claims 2 Drawing Figures "III 5 'illllll G dimmin- I I i p/||||||II|| g Q) 3' 10b PATENTEHMAY 141974 SHEET 2 OF 2 lOb IOb

ll-lul IHHM i lll flww D i FIGZ PATTERNING MECHANISMS FOR KNITTINGMACHINES This invention relates to electromagnetically operatedpatterning mechanism for' knitting machines. It has particular referenceto such mechanisms of the type described in U.S. Pat. No. 3,550,398 andis an improvement in or modification of the invention described andclaimed in that patent.

It will be appreciated that, in applying electronic and,electro-magnetic devices to control the patterning mechanism ofknitting machines, various limitations are imposed on the design of thecontrolling devices particularly when they form an integral part of thepatterning mechanism. For instance, if the actual selection of theneedles is obtained in conventional .fashion e.g. by a bank of selectorslocated close to a needle cylinder and acting directly upon buttsassociated with the needles, then the electro-magnetic devices forcontrolling the bank of selectors must be confined in a small spaceunless considerable re-design of the knitting machine is carried out.

In the case of patterning mechanism in which each selector of theaforementioned bank is controlled by an electro-magnetic coil it followsthat a number of electro-magnetic coils will be situated in closeproximity to one another and this'can give rise to faulty actuation ofthe selector levers due to the magnetic fields of the different coilscausing unwanted interference with one another. The actual effect of theinterference is such that, when an electric pulse is produced in aparticular coil in order to-obtain an effect upon its associatedselector lever, then, should other coils in the assembly also be pulsedsubstantially simultaneously, the magnetic field created by the othercoils may cause the selector lever associated with the particular coilto malfunction to such an extent that the selector lever is not operatedin the desired manner.

An object of the presentinvention is to provide, in association withpatterning mechanism of. a knitting machine, an assembly of closelysituated magnetic coils each controlling a selector and which arecapable of being energised in any particular sequence, or in'any numbersimultaneously, without causing malfunction of the selectors. It isnaturally economically desirable for this to be achieved in as simpleand inexpensive a manner as possible.

According to the invention there is provided a patterning mechanism fora knitting machine in which means is provided to'constrain the magneticflux produced by the electromagnetic means to follow a predeterminedindividual magnetic'path whereby the influence of any electro-magneticmeans upon any selector other than the associated selectoris reduced tonegligible proportions.

The constraining means is preferably in the form of material of veryhigh permeability.

More specifically, in the case where each electromagnetic meanscomprises a permanent magnet and a single coil, there is provided inassociation with each of g the coils a shelf in the form of a strip orbar of magnetic material and which is disposed in such a way that themagnetic flux produced by the associated coil when energised is guidedor folded in a more constrained path by virtue of its passage throughthe strip or bar. In this way, not only is interference with adjacentcoils minimized, but also leakage of the magnetic flux is minimized. 7

When putting the invention into practice the strip or bar, which may bemade of soft iron, can be arranged in the form of a shelf or support forthe coil and magnet associated with it, the shelves and coils combiningto form part of a compact unit which includes the bank of selectorelements.

Whilst the invention is applicable to most types of knitting machine,both flat and circular, it will now be described in detail withreference to the accompanying drawings as applied to a circular machineof the revolving cylinder type equipped with patterning mechanism of thetype described in the US. Pat. No. 3,550,398. It will be appreciatedthat in showing the invention as applied to this particular patterningmechanism it is not limited to such an arrangement and may be used inall cases where the close spacing of electro-magnetic coils isdesirable.

In the drawings:

FIG. 1 is a sectional side view through part of the needle cylinder andassociated parts of the knitting'machine, showing the knittinginstruments and a patterning unit; and

FIG. 2 is a perspective view of some of shown in FIG. 1.

In FIG. 1 a rotary needle cylinder 1 is shown provided with tricks 2which house needles 3. Also provided in the tricksare spring jacks 4 androcking pressers 5 the arrangement being that the needles 3 and springjacks 4 are vertically displaceable in the cylinder tricks 2 while thepressers 5 are restrained from vertical movement by their engagementwith a fulcrum ring 6 about which they may be rocked.

Rocking of a presser 5 in the anti-clockwise direction as viewed in FIG.1 causes depression of a pattern butt 4a of the spring jack into itstrick 2 so that it passes behind a raising cam 7 and is not raisedthereby.

Thepressers are rocked outwardly at their upper end by a cam 8 acting onthem seriatim as the needle cylinder revolves. This action brings theupper ends of the rockers into the influence of a permanent magnet 9which retains the rockers after they pass beyond the cam 8. The butt 4ais then depressed into the-trick 2. It is only necessary to pushselected pressers 5 off the magnet 9 in order to allow the depressedbutts 4a of the jacks 4 to spring out and engage the raising cam 7 forsubsequent operation of the needles.

To carryout this selective pushing of pressers 5 off the magnet, a bankof selectors, shown generally at 10 the parts in FIG. 1, is arranged ina unit 11 adjacent the needle cylinder 1 and the rocking pressers 5.Each presser 5 is provided with a butt 5a and the butts of consecutivepressers are arranged in selected spaced horizontal planes equal innumber to the number of selectors 10 in the bank. In their inactiveposition the selectors 10 have their operating camming ends 1012 inplanes between the planes of the butts 5a which planes are sufficientlyspaced apart vertically to allow the butts 5a to miss the selector ends1012 when they are in the inactive position. Movement of a selector toactive position causes its end 10b to lie in a plane of a butt 5a sothat the camming edge will push on the butt 5a and disengage the upperend of the presser 5 from the magnet 9.

Each selector is in the form of a first order lever with one armcarrying the end 10b and the other arm 10a made of soft iron, passingthrough an associated electro-magnetic coil. The movement of theselectors from an operative position to a non-operative position andvice versa, is brought about by the series of electromagnetic coils 12(see FIG. 2) through which the soft iron arms 10a of the selectors 10pass, with an extreme end 100 of each selector locating in between thetwo poles of a permanent magnet 13.

When the electro-magnet coil 12 associated with a particular selector 10is energized it causes the arm 10a of the selector to become magnetizedand, depending upon the polarity of the energization, the polarity ofthe selector arm 10a will be north or south. It will therefore beattracted to one of the two poles of the permanent magnet 13 andrepelled from the other. By pulsing the coil in opposite polaritiesaccording to a predetermined sequence, the selector can be moved betweenoperative and inoperative positions as desired.

Because patterning mechanism of this type must be operated at extremelyhigh speeds, it will be appreciated that the coils associated with abank of selector levers must be pulsed at a very rapid rate (e.g. morethan 100- times per second) and any oneselector arm 100 may be attractedto one pole of the permanent magnet 13 and almost immediately repelledtherefrom by a change of polarity and attracted to the opposite pole. Itis natural that a certain amount of bounce can take place as theselector end 10c strikes the pole face of the magnet 13 and it can beappreciated that, unless the mutual attraction of the selector end 10cand the particular pole face of the magnet 13 is strong, there is apossibility that the selector will not adhere properly to the selectedpole face. This strong mutual attraction can be impaired if themagnetization of the selector'end 10c is not efficiently achieved.Should the pattern of electric pulses in the closely situated coils besuch that a strong magnetic flux of one polarity is created then aselector may well be influenced in mid-bounce to be attracted to thewrong pole face.

in the specific arrangement under discussion, in accordance with theinvention, there is associated with each selector arm 10a and itsassociated coil 12 and permanent magnet 13, a strip 14 of soft ironwhich is arranged in such a position that the magnetic flux created bythe coil is constrained to follow a magnetic circuit around the arm 10a,coil 12 and the appropriate pole of the magnet 13. Loss of magnetizationin the selector arm 10a is therefore reduced to a minimum and themagnetic flux generated by the coil 12 is substantially prevented fromaffecting adjacent selectors.

Depending upon different conditions determining the size, configurationand location of the selectors, coils and magnets, various arrangementsof the strips 14 may be decided upon, and the example shown in FIG. 2 isone in which the strips are in two vertical rows and staggeredrelatively to one another. The strips 14 have also been adapted to formshelf-like supports for the associated coils and magnets, the shelvesbeing slotted into side walls 11 of the selector unit.

Various modifications may be made within the scope of the invention.

We claim:

1. In a patterning mechanism for a knitting machine of the typecomprising a bank of selector elements each associated with individualelectro-magnetic means for movement between selection and non-selectionpositions and wherein each of the electro-magnetic means comprises apermanent magnet and a single coil, the improvementwhich comprises: aseparate shelf of high magnetic permeability for each of theelectro-magnetic means to constrain the magnetic flux produced by theindividual electro-magnetic means to follow predetermined individualmagnetic flux paths whereby the influence of any of the electro-magneticmeans upon any selector element other than the selector elementassociated therewith is reduced to negligible proportions, said shelfsupporting the magnet and coil associated therewith.

2. A patterning mechanism as claimed in claim 1, in which the shelf issoft iron.

3. A patterning mechanism as claimed in claim 1 in which each shelf isin the form of a strip or bar and which is disposed in such a way thatthe magnetic flux produced by the associated coil when energised isguided in a more constrained path by virtue of its passage through theshelf.

4. A patterning mechanism as claimed in claim 1, comprising a compactpatterning unit into which all of the shelves and coils are assembled,with the bank of selector elements.

1. In a patterning mechanism for a knitting machine of the typecomprising a bank of selector elements each associated with individualelectro-magnetic means for movement between selection and non-selectionpositions and wherein each of the electromagnetic means comprises apermanent magnet and a single coil, the improvement which comprises: aseparate shelf of high magnetic permeability for each of theelectro-magnetic means to constrain the magnetic flux produced by theindividual electromagnetic means to follow predetermined individualmagnetic flux paths whereby the influence of any of the electro-magneticmeans upon any selector element other than the selector elementassociated therewith is reduced to negligible proportions, said shelfsupporting the magnet and coil associated therewith.
 2. A patterningmechanism as claimed iN claim 1, in which the shelf is soft iron.
 3. Apatterning mechanism as claimed in claim 1 in which each shelf is in theform of a strip or bar and which is disposed in such a way that themagnetic flux produced by the associated coil when energised is guidedin a more constrained path by virtue of its passage through the shelf.4. A patterning mechanism as claimed in claim 1, comprising a compactpatterning unit into which all of the shelves and coils are assembled,with the bank of selector elements.